Clamp means for duplicator cylinders



Oct. 2, 1951 P. A. STEPHENSON CLAMP MEANS FOR DUPLICATOR CYLINDERS Filgd Jan. 11, 1949 INVENTOR 2 Sheets-Sheet l Paul/I. SZ

1951 P. A. STEPHENSON ,5 ,738

CLAMP MEANS FOR DUPLICATOR CYLINDERS Filed Jan. 11, 1949 2 Sheets-Sheet 2 INVENTOR. Paul A. Stephenson 146w d it) Atty.

Patented Oct. 2, 1951 CLAMP MEANS FOR DUPLICATOR CYLINDERS Paul A. Stephenson, Evanston, 111., assignor to A. B. Dick Company, Chicago, 111., a corporation of Illinois Application January 11, 1949, Serial No. 70,299

8 Claims. (Cl. 101-415.1)

This invention relates to the printing cylinder of duplicating machines and more particularly to the clamping means of such cylinders whereby a printing member, such as a duplicating stencil or other master copy, is secured in operative position on the cylinder. It has for its primary object to provide simple and efficient clamping means of the character designated by which the operation of changing the printing means may be considerably expedited without risk of damaging the clamp parts or the machine.

Another object of the invention is to provide clamping means by which the printingmember may be changed without getting ink on the clamp or onthe hands of the operator.

A further object of the invention is to provide clamping means which may be used with equal facility to secure printing members of different construction and type.

The invention is particularly applicable to duplicating machines which employ stencils, and it has been specifically described in connection with such a machine, but it is to be understood that the invention is also applicable to duplicators using other kinds of printing members. In the operation of changing stencils on such duplicators, it has been heretofore necessary first to open the rear or tail clamp and remove the lower end of the stencil. The cylinder is then turned back so as to expose and permit disengagement of the head or leading end of the stencil, which is then removed. Usually the cylinder cannot be turned back while the rear clamp is in its open position without striking adjacent parts of the machine, and it has been common practice, for this reason, to close the tail clamp after that end of the stencil has been removed. This brings the clamping edge in direct contact with the ink pad and transfers ink to the outside of the clamp. If not first removed, this ink will be later offset to the impression roller, and from the roller to the backs of prints, which are thus spoiled. Accordingly, it has been necessary to hand wipe the excess ink from the clamp parts before the machine is again run, and this is a dirty and time-consuming operation.

The present invention provides clamping means by which the tail clamp member, after being fully opened to remove the stencil, may be nearly closed, sufficiently to permit turning back of the cylinder but without being brought into contact with the ink pad. The clamp is retained in this intermediate, nearly closed position during the changing operation until the cylinder has been returned. to its original position for reception of the lower end of the new stencil. The clamp may then be again fully opened for insertion of the stencil without the necessity of touching any of the inked parts, and the opening, partial closing and reopening of the clamp, may all be effected by manipulation of the usual clamp operating lever only, so that no ink is deposited on the clamp parts, and no cleaning operations are necessary. The invention also provides a simple and very rapid means for cocking the clamp operating mechanism so that the clamp may be finally tightly engaged on the stencil to hold it in position on the duplicating cylinder.

Various other objects of the invention will appear from the following description taken in connection with the drawings, which form a part of this specification, and in which:

Fig. 1 is a perspective view of a well-known type of duplicator embodying the invention, showing the tail and side clamps of the cylinder in closed position.

Fig. 2 is a view in elevation of the interior of one of the head members 18 of the duplicator cylinder, showing the arrangement of the clamps and the operating mechanism thereof, partly in section.

Fig. 3 is a fragmentary view in plan of a portion of the duplicator cylinder over the tail clamp, partially broken away and partially in section to show details of the clamp operating mechanism.

Fig. 4 is a plan view similar to Fig. 3 over the head clamp, partially in section, substantially on the line 4-4 of Fig. 2.

Fig. 5 is a fragmentary view of a part of the mechanism shown in Fig. 2, showing the tail clamp in fully opened position.

Fig. 6 is a fragmentary view of a part of the mechanism shown in Fig. 2, showing a side clamp in fully opened position.

Fig. '7 is a fragmentary plan view of the underside of the lower plate 32 of the head clamp.

Fig. 8 is a view in section through the head clamp, taken substantially on the line B8 of Fig. 7.

Fig. 9 is a perspective view of a portion of the duplicator and cylinder shown in Fig. 1, the tail clamp being in fully open position, showing the method of cocking the operating mechanism to completely close the tail clamp.

Referring to the drawings, at In in Fig. 1 is shown generally a stencil duplicatingmachine of well-known type to which the present invention is applicable. The machine [0 comprises a base or frame ll including spaced side members [2 between which the printing cylinder I3 is rotatably mounted. Cylinder l3 cooperates with a suitable impression roller, not shown, to form the printing couple of the machine. Associated with the frame is a feed table l4 and a receiving tray i3, and the side members l2 are rigidly connected by cross members as at l5 adjacent the cylinder, to strengthen the structure and to support various accesories, not shown. The machine may also be provided with a hand wheel or crank ll and with the usual switches, counters, and other accessories as needed or desired. Cylinder I3 is adapted to be driven through suitable gearing from an electric motor, not shown, and may also be hand operated or adjusted on its axis by turning the hand wheel I! in the usual-way. Since duplicating machines of this general character are well known in the art of stencil duplication, further detailed description is unnecesary and omitted.

The printing cylinder l3 comprises a pair of circular, flanged head members l8 which carry the journals on which the cylinder is mounted. Connecting and rigidly secured to the heads I8 is a cylindrical printing member IQ of well-known construction best shown in Fig, 9, including a foraminous diaphragm portion 2| adapted to support an ink pad or other inking member 22 and the stencil or printing member 23, and to pass ink to the stencil from an ink reservoir of any well-known construction, not shown, located within the cylinder. At each end of the diaphragm 23, the printing area terminates in a cross-bar 24, shown in Fig. 2, extending across the cylinder between the heads I8 and rigidly secured thereto. These bars 24 form end abutments over which the ink pad 22 is stretched and against which the stencil 23 is clamped to secure it in printing position on the cylinder.

The stencilclamping means of this invention includes an end or tail clamp member 26, adapted to retain the lower end of the stencil 23, and side clamp members 21 adapted to retain the side edges thereof. These clamp members cooperate with a head clamp member 26 suitable for securing and retaining the leading end of the stencil and adapted to receive either the type of ally, inturned flanges 29 by which it is pivotally mounted on trunnions 3| on the head members l8 so that its edge may be swung into clamping engagement with the adjacent clamp bar 24. Beneath the member 28 is a similarly disposed plate 32 having end flanges 33 which are pivoted on the trunnions 3|; inside the flanges 29. Disposed between the clamp member 28 and the plate 32 is a stop member 34, also provided with end flanges 35 by which it is pivotallymounted on the trunnions 3| inside the flanges 33. The stop member 34 is provided-at its forward edge with a number of inwardly disposed stop fingers 36 adapted to pass through correspondingly spaced apertures 31 in the plate, 32; these fingers and apertures being so arranged as to define a stop line across the cylinder, spaced a short distance from theedge of the plate 32 to determine the depth of insertion for proper clamping of a stencil. of the stubless type. The. rear end of the member 34 is also formed with upturned flanges 36 .which form a stop to determine. the depth of insertion for proper clamping of stencils of the conventional type having a wide stub provided with buttonholes. Leaf springs 38, mounted on the upper surface of the plate 32 has been 4 and bearing against the under surface of the member 34 urge these members apart, which movement apart is limited by a tongue 39 secured to the under side of member 34 and projecting through an opening in the plate 32. This tongue is engaged by a cam latch 4|, pivotally mounted on the lower face of plate. 32, as best shown in Fig. '7, and provided with a suitable handle by which the member 34 may be rocked on its pivots against the springs 38 to move the fingers 36 through the apertures 31. The clamp member 28 and the plate 32 are also urged apart by transverse leaf springs 48 mounted on the lower face of the plate 32: and bearing on the flanges 29.

Disposed across the cylinder adjacent the clamp bar 24 and below the spacer plate 32 is a rock shaft 42, pivotally mounted in suitable bearings 43 carried by the head members and project ing through one of said head members for opera tion by a suitable hand lever 44 secured to the projecting end thereof. The shaft. 42" carries near its. ends a pair of locking cams 46 which are disposed inside the head members l8 and which are adapted to engage over rollers 41 mounted on pins 48 carried by the flanges 29. The cams 46 are so shaped as to draw down the rollers and close and lock the clamp member 26 when the shaft 42 is turned by the lever 44. The'lower plate 32 is also provided with apair of spring clips 45 adapted resiliently to engage over the shaft 42 and thus retain the plate in closed po sition with its toe edge in contact with the abutment 24, as shown in Fig., 2. The clips45 may be readily sprung out of engagement, however, when it is desired to lift the lower plate and the head clamp assembly for any reason, as for ex ample, to change the ink pad'2 2.

It will be apparent from the foregoing descrip; tion that the head clamp is readily adaptable to receive and secure either of the more usual types of stencils If the stencil to be clamped is of the type having a long stub, the opera-toywill depress the stop member 34 by means of the latch 4| and will then insert the stub end of the stencil between the member '34 and the clamp memberv 28 until its edge is in contact with the flanges 36 If, however, the stencil-is one the type having a very short stub, then the operator will disengage the latch 4| so that the plate 34 will be raised by the springs 3'8, in which position the fingers 36 define astop wall across the clamp opening. He will then insert the head of the stencil until it comes in contact with the fingers 36. In either case, after the stencilhas been inserted, the operator will then close the clamp assembly by moving the hand lever 44 to actuate the locking cam 46, whichwill tightly clamp the stencil between the edges of the mem ber 28 and 32-. This operation is quickly and easily performed without danger of soiling the hands or of getting ink on the machine parts. 7

The tail clamp member 26 also extends axially across the cylinder |3 in a manner similar to the head clamp 28, being curved/on its outer surface to conform to the cylindrical surface of the diaphragm 2|, and it is formed at each end with radially, inturned flange portions 5|and 521 The flanges 5| are extended beyond therear orheel edge of the clamp and are pivotally mountedjon a cross shaft. 53 extending across the cylinder I3 between the head members I8, sothat the toe or clamping edge of the member 26 may be swung into and out of clamping engagement with the cooperating clamp barv or abutment 24. p A suitable coil spring 56, surrounding the shaft 53. and engaging the flange 5|, urges the member amazes 26- toward its open position; The flanges 52 are each provided with a stud 51 through which the clampmember 26 may be operated by suitable mechanism, presently to be described.

Journaled in the heads l8 and projecting through one of them is an operating shaft 58 which extends across the cylinder [3, parallel to the shaft 53, and carries at its projecting end a suitable lever 59 by which it maybe operated. The lever 59 is arranged to lie close to the outsideface of the adjacent head It, and it is prob erably curved so as to conform, when in closed position, to the circle of the rim of the head.

The shaft 55 operates actuating mechanism for the clamp member 26 which will be understood to'be mounted in duplicate on the inside of. each of th head members and to operate in unison on each end of the clamp. This mechanism includes a lever arm i, rigidly secured to the shaft 58 and pivotally connected at its outer end to a curved link memberliil as by a pivot 63.. l he other end of the link member 62 is provided with a slot 54 cooperating with a pin it on one end of a bell crank lever 5?. The bell crank 6'1 is mounted for pivotal movement about a stud 68 fixed in and projecting inwardly from the head D8. The pin 66 projects through theslot 64 so as to form a lost motion connection between the bell crank. lever El' and the curved link 62, and this pin is connected to one end of a tension spring 69 of which the other end is connected to a suitable abutment "ii on the link member 62. The link 52 is socurved as to extend aroundthe shaft 58, which permits its end 53 to cross the dead center position defined by the line passing through the axes of shaft 55 andthe pin 55. The arm iii and the link 52 thusform a toggle which may be yieldingly locked in its closed position by the tension spring '69.

The other end of the bell crank lever 6! is pivotally connected as at E2 to an operating link 73, one side of which is formed in a substantially straight guide portion M. This link I3 terminates in an enlarged head portion it adjacent the corresponding flange 52 of the clamp member contact with the pin 8! by means of a tension spring 82 connected between suitable abutments 83 and ti l on the link 13 and on the bell crank lever 61 respectively.

It will be evident that the" distance from the pivot 12 to the notch i9 is somewhat greater than the distance from this pivot to the notch 18 so that the effective length of the link 73 may be changed, depending upon which notch is engaged by the stud 51. These parts are so designed that a given angular movement of the bell crank lever 61 will move the link 13 to close and clamp the toe of the member 26 against the abutment 24 when the stud 51 is engaged in the notch Hi. When the stud is engaged in the notch 19, the same movement of th bell crank lever 61 will bring the member 26 into the position illustrated in dotted line in Fig. 2, in which the clamp is nearly closed but is spaced out of actual contact with the abutment 24 by a small amount.

It will be evident that as the bell crank lever 61 moves to actuate the link T3,.the lower-end of thelinkmoves in the .arc of a circle about the center: 68 by reason of pivotal connection at '12, and that the head end Tsof the link it: moves in a path which; by reason of the guiding or cam action of the member. 8! has the effect of turning the axis of the notches it-19 counterclockwise. 'On the other hand, the path of the stud 57 describes an are about the center 53 as the clamp member is opened. As the clamp member approaches its nearly open position, the slight rotation of thehead it releases the stud 5'! from notch 18, and thespring moves the clamp member and with it the stud 5:57 to automatically seat the'stud in the notch it. Accordingly, the operation of opening the clamp member 26 to its wide open position automatically shifts the stud 51 to the notch l9 so that when the lever 59 is thereafter moved towards closing position, the clamp will be closed only as far as the position shown in dotted lines, Fig. 2. It is thus spaced a small amount out of actual contact with the inked parts. The cylinder I 3 may now be turned back without striking the clamp member 26 on any of the cross members It or other closely adjacent portions of the machine.

After the head end of the new stencil has been clamped in the head clamp 28, the cylinder 13 is now turned forward to the tail clamp position, and the tail clamp 26 is again fully opened by means of the lever 59. In this position the end of the new stencil is laid in position on the ink pad 22 over the clamp abutment 2A, and the clamp 26 is again swung towards closed position by means of the lever 5% After this movement has commenced, the stud 5'! may be returned from the notch l9 to the clamping notch in by giving the clamp a slight touch with the hand in the manner illustrated in Fig. 9. This cocking action returns the actuating mechanism to its original position, so that continued movement of the lever 59 will draw the clamp down into tight clamping engagement with the stencil.

The side clamp members 27 are mounted on the heads I8 adjacent the clamping edge of the tail clamp 26 and are adapted to engage the side edges of the stencil; Each of these clamps comprises an arcuate flange portion having the same curvature and radius as the cylinder and projecting axially inward over the printing member l9, these flanges being substantially flush with the rims of the heads it when the clamps are engaged. Each of the clamp flanges 21 is formed with an integral segmental portion or member 86, mounted on the inner face of the head it and guided to slide radially thereon in any suitable way, as by means of headed pins or screws 81 cooperating with bayonets slots 88 formed in the segmental portion 86. The rim of each head is notched or cut away to accommodate these clamp portions 86, as best shown at 89 in Fig. 3.

The side clamps are operated in unison to engage the side edges of the stencil 23 by means mounted on the inner surface of the head l8 and operatively connected to and actuated from the tail clamp operating mechanism. This includes for each clamp 21, a lever 9i, pivotally mounted on a suitable pin 92 and provided at its inner end with a slot 93, which is engaged by a pin 94 on a portion of the bell crank lever 61 to form therewith a lost motion connection. The lever 9| carries a pin 96 rigidly mounted thereon to project through a circular opening 9'! of somewhat larger diameter in the segmental clamp member 86. This member 86 also carries a leaf spring'98, .the ends of which engage ears 99 formed on the edges of the member and which is provided in its central portion with a bend llll adapted to engage the pin 96.

It will be understood that the operating mechanism just described provides means for exerting a spring clamping pressure on the clamping members 21 in the closed and clamped position and for positively opening the clamps after a certain degree of lost motion, so that the side clamps will remain closed when the tail clamp Z6v is in theslightly open position illustrated in Fig. 2. However, as the bell crank lever is actuated to the position shown in Fig. to fully open the tail clamp 26, the pin 94 first moves to the inner end of the slot 93, and upon further movement rotates the lever 9! on its pivot 92 so that the pin 96 releases the load on the spring 98. Continued opening movement of the lever 9| moves the pin 96 against the outer side of the opening 91, thus eXerting a direct pressure on the member 86 to slide it radially outward on its guide pins to open position of the clamp 21.

The operation of the clamping means of my invention has been described in connection with the foregoing description and will be readily understood. Although the invention ha been described in connection with a specific embodiment, it is susceptible of other applications which will readily occur to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims. -What I claim and desire to secure by Letters Patent is: v

1. Stencil clamping means for duplicating machines comprising a pivotally mounted clamp member, actuating means for said clamp member including a toggle, links operatively connected to said actuating means, said links being provided at one end with a notched slot, and pins carried by the clamp member adapted to selectively engage the notches of said slot.

2. Stencil clamping means for duplicating machines comprising a pivotally mounted clamp member, actuating means for said clamp member including a toggle, links connected through the toggle to said means formed with notches to selectively vary the efiective radius of said links, and pins on the clamp member adapted to seat selectively in said notches.

3. Stencil clamping means for a duplicator cylinder comprising a clamp member pivotally mounted on the cylinder, actuating pins fixed to said clamp member, spring means urging the clamp member toward open position, and linkage comprising a pivotally mounted clamp member adapted to engage an element of the cylinder, a link having a head portion at one end defining notched seats, one of said seats being nearer to the opposite end of said link than the other said seat, a pin on said clamp member adaptedto engage alternatively in said seats, and means to move said opposite end of the link to actuate said clamp member.

5. Clamping means for a duplicator cylinder comprising a clamp member pivotally movable into clamping engagement with an element of said cylinder, a pin fixed on said clamp member, a link formed with spaced notches each adapted to engage said pin and arranged at different distances from the end of the link, actuating means connected to the link, and means for automaticall changing the pin position at the end of the link stroke to the notch furthest from the end of the link.

6. Clamping means for a duplicator cylinder comprising a clamp member pivotally movable into clamping engagement with said cylinder, a link formed with spaced notches arranged at different positions thereon to change the effective length thereof, actuating means for an end'of said link, connecting means carried by the clamp member adapted to seat automatically in said notches, and means including a guide stud engaging said link adapted to automatically change the pin position to the notch furthest from the actuating means at the end of the link stroke.

'7. Clamping means for a duplicator cylinder comprising a pivoted clamp member, a spring urging said clamp member toward open position, a link formed at one end with spaced notches defining different effective lengths of the link, means to actuate the other end of said link, and connecting means carried by theclamp member adapted to seat in said notches, one of said notches corresponding to partially open clamp position, and the other notch corresponding to fully closed clamp position.

8. Clamping means for a duplicator cylinder comprising a clamp member movable toward and from clamping engagement with an element of the cylinder, a link, means to actuate and guide an end of the link in a fixed path, guide means for engaging said link intermediate its ends, and means connecting said link adjacent its other end to the clamp member, said connecting means being operable in response to the guided motion iii the link to change the efiective length of said ink.

PAUL A. STEPHENSON.

REFERENCES CITED UNITED STATES PATENTS Name Date Brasseur July 13, 1926 Number 

